This invention relates to a tool holder in a machining center, and more particularly, a tool holder in a machining center by which small tools can be interchangeably mounted on a basic tool holder.
It has of late been increasingly demanded that with a use of a single machining center, different works should be effectively processed and/or a multi-stage processing should be possibly perfomed. To meet this demand, it is proposed to have a tool magazine of the machining center with a wide variety of tools.
The kind of tools generally used in such machining center a drill used for about 40% of the processing, a small diameter end mill for about 15% of the processing, a tap for about 20% of the processing, and a large-sized cutting tool for roughing works for about 25% of the remainder of the processing.
About 75% of the tools installed on a large spindle of the machining center are small-sized tools for cutting.
With conventional tool magazines in machining centers, the number of tools that can be accommodate is limited. It is often infeasible to machine all of a variety of works by a single setting of tools. It is conceivable to enlarge the tool magazine so as to increase the number of tools to be therein stored. However, there still remains problems in the space requirement of the entire machine and economical reasons.
Consequently, where a machining cannot be finished by a single setting of tools on the conventional machining center, one must have the machine redriven, whereby the machining efficiency is adversely affected.
In the machining center where small tools are prevailingly utilized, there has not been proposed a tool holding arrangement or device in which changing of small tools and ordinary tools can be performed automatically and efficiently.